Polymorphic voltage pulse train for uniformity and etch profile tuning

Abstract

Embodiments of the disclosure provided herein include a method for processing a substrate in a plasma processing system. The method comprises the following steps: receiving a first synchronous waveform signal from a controller; after receiving a first portion of the first synchronization waveform signal, delivering a first pulse train of a first voltage pulse to an electrode assembly wherein at least one first parameter of the first voltage pulse is set to a first value based on a first waveform parameter within the first portion of the first synchronization waveform signal; and delivering a second pulse train of a second voltage pulse to the electrode assembly after receiving a second portion of the first sync waveform signal, wherein the at least one first parameter of the first voltage pulse is set to a second value based on a difference in the first waveform parameter within the second portion of the first synchronization waveform signal.

Description

Technical Field

[0001] Embodiments described herein generally relate to semiconductor device manufacturing hardware and processes, and more particularly to apparatus and methods for controlling the delivery of power to a plasma formed in a plasma processing chamber used in semiconductor manufacturing. Background Art

[0002] A typical reactive ion etch (RIE) plasma processing chamber includes a radio frequency (RF) bias generator that supplies an RF voltage to a "power electrode" (e.g., a bias electrode), such as a metal plate located near an electrostatic chuck (ESC) assembly, more commonly referred to as a "cathode". The power electrode can be capacitively coupled to the plasma of the processing system through a layer of thick dielectric material (e.g., a ceramic material) that is part of the ESC assembly. In a capacitively coupled gas discharge, the plasma is generated by using a radio frequency (RF) generator that is coupled to an RF electrode through an RF matching network ("RF match"), which tunes the apparent load to 50 Ω to minimize reflected power and maximize power delivery efficiency. Applying an RF voltage to the power electrode causes a plasma sheath layer (also known as a "cathode sheath") that repels electrons to form above the processing surface of the substrate, which is positioned on the substrate support surface of the ESC assembly during processing. The non-linear, diode-like characteristics of the plasma sheath cause rectification of the applied RF field, such that a direct-current (DC) voltage drop or "self-bias" appears between the substrate and the plasma, making the substrate potential negative with respect to the plasma potential. This voltage drop determines the average energy at which plasma ions are accelerated towards the substrate and thus anisotropic etching occurs. More particularly, ion directionality, feature profiles, and etch selectivity to masks and stop layers are controlled by the Ion Energy Distribution Function (IEDF) and the Electron Energy Distribution function (EEDF). In a plasma with RF bias, the IEDF typically has two non-discrete peaks, one at low energy and the other at high energy; and a population of ions with an energy range that extends between the two peaks. The presence of the population of ions between the two peaks of the IEDF reflects the fact that the voltage drop between the substrate and the plasma oscillates at the RF bias frequency. When a lower frequency RF bias generator is used to achieve a higher self-bias voltage, the energy difference between the two peaks can be significant; and since the etching profile caused by ions at the low energy peak is more isotropic, this can result in the bending of the etched feature walls. Compared to high-energy ions, low-energy ions are less efficient at reaching the corners at the bottom of the etched feature (e.g., due to charging effects), but cause less sputtering of the mask material. This is important in high aspect ratio etching applications, such as hard mask opening or dielectric mold etching.As feature sizes continue to decrease and aspect ratios increase, while at the same time feature profile control requirements become more stringent, it is increasingly desirable to have well-controlled IEDF and EEDF at the substrate surface during processing.

[0003] Other known plasma processes and processing chamber designs have also found that delivering multiple different RF frequencies to one or more electrodes in a plasma processing chamber can be used to control various plasma properties, such as plasma density, ion energy, and / or plasma chemistry. However, it has been found that delivering multiple known sinusoidal waveforms from two or more RF sources (each RF source configured to provide a different RF frequency) does not adequately or ideally control sheath properties and can lead to undesirable arcing issues. Additionally, due to direct or capacitive coupling between RF sources during processing, each RF source may induce an RF current that is supplied to the output of other connected RF sources (e.g., commonly referred to as "crosstalk"), resulting in power deviation from the intended load (the plasma) and potentially causing damage to the individual RF sources within the RF sources.

[0004] Accordingly, there is a need in the art for novel, robust, and reliable plasma processing and biasing methods that enable maintaining an almost constant sheath voltage and thus generating a desired and repeatable IEDF and EEDF at the substrate surface to enable precise control of the etch profile of features formed in the substrate surface. SUMMARY OF THE INVENTION

[0005] Embodiments of the disclosure herein include a method for processing a substrate in a plasma processing system. The method will include: receiving, by a waveform generator, a first synchronized waveform signal from a controller; after receiving a first portion of the first synchronized waveform signal, delivering, by the waveform generator, a first train of first voltage pulses to an electrode assembly disposed within the plasma processing system, wherein at least one first parameter of the first voltage pulses is set to a first value based on a first waveform parameter within the first portion of the first synchronized waveform signal; and after receiving a second portion of the first synchronized waveform signal, delivering, by the waveform generator, a second train of second voltage pulses to the electrode assembly disposed within the plasma processing system, wherein the at least one first parameter of the first voltage pulses is set to a second value based on a difference in the first waveform parameter within the second portion of the first synchronized waveform signal. In some embodiments, the first voltage pulses and the second voltage pulses are asymmetric voltage pulses.

[0006] Embodiments of the disclosure provided herein may also include a method for processing a substrate in a plasma processing system. The method will include: receiving, by a waveform generator, a first synchronization waveform signal from a controller of the plasma processing system; delivering, by the waveform generator, a first train of first voltage pulses to an electrode assembly disposed within the plasma processing system based on a first waveform pulse provided within the first synchronization waveform signal; and adjusting, by the waveform generator, at least one first parameter of the first voltage pulses between a first set of values based on characteristics of the first waveform pulse provided within the first synchronization waveform signal and between a second set of values based on characteristics of the first waveform pulse provided within the first synchronization waveform signal.

[0007] Embodiments of the present disclosure provided herein may also include a plasma processing chamber that includes: a voltage waveform generator configured to deliver a first pulsed voltage waveform to an electrode assembly disposed within the plasma processing chamber; a controller; and a memory for storing a program to be executed in the controller. The program includes instructions that, when executed, cause the voltage waveform generator to: receive a first synchronization waveform signal from the controller; after receiving a first portion of the first synchronization waveform signal, deliver a first train of first voltage pulses to the electrode assembly disposed within the plasma processing system, wherein at least one first parameter of the first voltage pulses is set to a first value based on a parameter of the first portion of the first synchronization waveform signal; and after receiving a second portion of the first synchronization waveform signal, deliver a second train of second voltage pulses to the electrode assembly disposed within the plasma processing system, wherein values of at least one first parameter of the second voltage pulses and the first pulsed voltage waveform are different based on a difference between the first portion and the second portion of the first synchronization waveform signal. The program may further include instructions for: delivering a third train of third voltage pulses after receiving a third portion of the first synchronization waveform signal, wherein at least one first parameter of the third voltage pulses is set to a third value based on a parameter of the third portion of the first synchronization waveform signal; and delivering a fourth train of fourth voltage pulses after receiving a fourth portion of the first synchronization waveform signal, wherein at least one first parameter of the fourth voltage pulses is set to a fourth value based on a parameter of the fourth portion of the first synchronization waveform signal, and the at least one first parameter of each of the voltage pulses is the same parameter. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] To be able to understand the above features of the present disclosure in detail, the present disclosure briefly summarized above may be described more specifically with reference to the embodiments, some of which are illustrated in the accompanying drawings. However, it should be noted that the drawings illustrate only exemplary embodiments and should not be considered as limiting its scope, and other equally effective embodiments may be allowed.

[0009] Figure 1 is a schematic cross-sectional view of a processing chamber according to certain embodiments, in which a composite load is formed during plasma processing.

[0010] Figure 2 Illustrates an example of a voltage pulse provided within a voltage waveform established at a substrate due to delivering voltage pulses to a bias electrode by using a PV waveform generator during plasma processing, according to certain embodiments.

[0011] Figure 3A and Figure 3B Illustrates that a train of pulses of a PV waveform generated by a PV waveform generator is delivered to a bias electrode, according to certain embodiments.

[0012] Figure 3C Illustrates an example of a pulse voltage waveform of a train of pulses constituting a PV waveform, according to certain embodiments.

[0013] Figure 3D Illustrates a PV waveform generated by a PV waveform generator based on a plurality of synchronization signals, according to certain embodiments.

[0014] Figure 4 Illustrates a method of using a plasma processing chamber, according to certain embodiments.

[0015] Figure 5 Illustrates a method of using a plasma processing chamber, according to certain embodiments.

[0016] Figure 6A and Figure 6B Each illustrates an exemplary asymmetric pulse voltage delivered to a bias electrode and a synchronization signal delivered to a PV waveform generator, according to certain embodiments.

[0017] Figure 6C Illustrates an exemplary asymmetric pulse voltage delivered to a substrate assembly and a synchronization signal delivered to a PV waveform generator, according to certain embodiments.

[0018] Figure 7 Illustrates a method of using a plasma processing chamber, according to certain embodiments.

[0019] Figure 8Illustrated is a method of using a plasma processing chamber in accordance with certain embodiments.

[0020] To facilitate understanding, wherever possible, the same reference numerals are used to denote common elements in the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated into other embodiments without further recitation. Detailed Description

[0021] Embodiments of the disclosure provided herein include apparatuses and methods for plasma processing a substrate in a processing chamber. More specifically, embodiments of the present disclosure describe a biasing scheme that is configured to provide an RF-generated RF waveform from an RF generator to one or more electrodes within a processing chamber and to provide a pulsed-voltage (PV) waveform delivered from one or more pulsed-voltage (PV) generators to one or more electrodes within the processing chamber. Generally, the generated RF waveform is configured to establish and maintain a plasma within the processing chamber, and the delivered PV waveform is configured to establish a desired sheath voltage across the substrate surface during one or more stages of a plasma process and thereby generate a desired ion energy distribution function (IEDF) and electron energy distribution function (EEDF) at the substrate surface during one or more plasma processing stages performed within the processing chamber. The plasma processes disclosed herein can be used to control the shape of the IEDF and EEDF and thereby control the interaction of the plasma with the substrate surface during processing. In some configurations, the plasma processes disclosed herein are used to control the profile of features formed in the substrate surface during processing. In some embodiments, the pulsed-voltage waveform is established by a PV generator that is electrically coupled to a bias electrode disposed within a substrate support assembly disposed within a plasma processing chamber.

[0022] During some semiconductor plasma processes, ions are purposefully accelerated toward a substrate by a voltage drop in an electron-repelling sheath formed above the substrate placed on top of a substrate support assembly 136. Although not intended to limit the scope of the disclosure provided herein, the substrate support assembly 136 is generally referred to herein as a "cathode assembly" or "cathode". In some embodiments, the substrate support assembly 136 includes a substrate support 105 and a support base 107. The substrate support 105 may include an electrostatic chuck (ESC) assembly that is configured to clamp (e.g., hold) the substrate on a substrate receiving surface 105A.

[0023] In some embodiments of the disclosure provided herein, the processing chamber is configured to provide capacitively coupled gas discharge such that a plasma is generated by using an RF generator assembly that includes an RF generator coupled to an RF electrode through an RF matching network (“RF match”). The RF matching network is configured to tune the apparent load to 50 Ω to minimize reflected power and maximize power delivery efficiency. In some embodiments, the RF electrode includes a metal plate positioned parallel to the plasma-facing surface of the substrate.

[0024] In addition, during the plasma processing method disclosed herein, an ion-accelerating cathode sheath is typically formed by using a pulsed voltage (PV) generator during plasma processing, and the PV generator is configured to establish a pulsed voltage waveform at one or more bias electrodes 104 disposed within a substrate support assembly 136. In some embodiments, the one or more bias electrodes 104 include a clamping electrode and optionally an edge control electrode. The clamping electrode is separated from the substrate by a thin layer of dielectric material formed within the substrate support assembly 136 (e.g., an electrostatic chuck (ESC) assembly), and the edge control electrode is disposed within or below an edge ring 114 surrounding the substrate 103 when the substrate 103 is disposed on a substrate support surface 105A of the substrate support assembly 136.

[0025] Example of a plasma processing chamber

[0026] Figure 1FIG. 0 is a schematic cross-sectional view of a plasma processing chamber 100 according to some embodiments, in which a composite load is formed during plasma processing. According to one or more embodiments, the plasma processing chamber 100 is configured to practice one or more of the biasing schemes presented herein. In one embodiment, the processing chamber is a plasma processing chamber, such as a reactive ion etch (RIE) plasma chamber. In some other embodiments, the processing chamber is a plasma enhanced deposition chamber, such as a plasma-enhanced chemical vapor deposition (PECVD) chamber, a plasma enhanced physical vapor deposition (PEPVD) chamber, or a plasma-enhanced atomic layer deposition (PEALD) chamber. In some other embodiments, the processing chamber is a plasma processing chamber or a plasma-based ion implantation chamber, such as a plasma doping (PLAD) chamber. In some embodiments, the plasma source is a capacitively coupled plasma (CCP) source that includes an electrode (e.g., chamber lid 123) disposed in the processing volume facing the substrate support assembly 136. In some configurations, a counter electrode (such as chamber lid 123) positioned opposite the substrate support assembly 136 is electrically coupled to ground. However, as Figure 1 shown, the counter electrode can alternatively be electrically coupled to a source 198 coupled to ground, such as a source including an RF generator or a PV generator. In yet another embodiment, the processing chamber alternatively or additionally includes an inductively coupled plasma (ICP) source electrically coupled to a radio frequency (RF) power supply.

[0027] The plasma processing chamber 100 also includes a chamber body 113, which includes a chamber lid 123, one or more sidewalls 122, and a chamber base 124. The chamber lid, one or more sidewalls, and the chamber base define a processing volume 129. The one or more sidewalls 122 and the chamber base 124 generally include materials that are sized and shaped to form a structural support for the components of the plasma processing chamber 100 and are configured to withstand the pressure and additional energy applied thereto when generating plasma 101 within the vacuum environment maintained in the processing volume 129 of the plasma processing chamber 100 during processing. In one example, the one or more sidewalls 122 and the chamber base 124 are formed of a metal, such as aluminum, an aluminum alloy, or stainless steel. A gas inlet 128 is disposed through the chamber lid 123 for providing one or more processing gases from a processing gas source 119 in fluid communication with the gas inlet to the processing volume 129. The substrate 103 is loaded into and removed from the processing volume 129 through an opening (not shown) in one of the one or more sidewalls 122, which is sealed with a slit valve (not shown) during the plasma processing of the substrate 103. Here, a lift and lower pin system (not shown) is used to transfer the substrate 103 to and from the substrate receiving surface 105A of the ESC substrate support 105.

[0028] In some embodiments, the RF generator assembly 160 is configured to deliver RF power to a support substrate 107 disposed near the ESC substrate support 105 and within the substrate support assembly 136. The RF power delivered to the support substrate 107 is configured to ignite and sustain a processing plasma 101 formed by using the processing gases disposed within the processing volume 129. In some embodiments, the support substrate 107 is an RF electrode that is electrically coupled to the RF generator 118 through an RF matching circuit 162 and a first filter assembly 161, both of which are disposed within the RF generator assembly 160. In some embodiments, the plasma generator assembly 160 and the RF generator 118 are used to ignite and sustain the processing plasma 101 by using the fields generated by the processing gases disposed within the processing volume 129 and the RF power provided by the RF generator 118 to the support substrate 107. The processing volume 129 is fluidly coupled through a vacuum outlet 120 to one or more dedicated vacuum pumps that maintain the processing volume 129 at sub-atmospheric conditions and evacuate processing gases and / or other gases from the processing volume. The substrate support assembly 136 disposed within the processing volume 129 is disposed on a support shaft 138 that is grounded and extends through the chamber base 124. However, in some embodiments, the RF generator assembly 160 is configured to deliver RF power to a bias electrode 104 disposed within the substrate support 105 relative to the support substrate 107.

[0029] As briefly discussed above, the substrate support assembly 136 generally includes a substrate support 105 (e.g., an ESC substrate support) and a support base 107. In some embodiments, the substrate support assembly 136 may additionally include an insulating plate 111 and a ground plate 112. The substrate support 105 is thermally coupled to and disposed on the support base 107. In some embodiments, the support base 107 is configured to regulate the temperature of the substrate support 105 and a substrate 103 disposed on the substrate support 105 during substrate processing. In some embodiments, the support base 107 includes one or more cooling channels (not shown) disposed therein that are fluidly coupled to a coolant source (not shown) (such as a refrigerant source) or a water source having a relatively high electrical resistance and are in fluid communication with the coolant source or the water source. In some embodiments, the substrate support 105 includes a heater (not shown), such as a resistive heating element embedded in the dielectric material of the substrate support. Herein, the support base 107 is formed of a corrosion-resistant thermally conductive material, such as a corrosion-resistant metal (e.g., aluminum, aluminum alloy, or stainless steel), and is coupled to the substrate support by an adhesive or by mechanical means.

[0030] The support base 107 is electrically insulated from the chamber base 124 by the insulating plate 111, and the ground plate 112 is interposed between the insulating plate 111 and the chamber base 124. In some embodiments, the plasma processing chamber 100 further includes a quartz tube 110 or collar that at least partially surrounds a portion of the substrate support assembly 136 to prevent the ESC substrate support 105 and / or the support base 107 from being corroded by contact with corrosive processing gases or plasmas, cleaning gases or plasmas, or their by-products. Generally, the quartz tube 110, the insulating plate 111, and the ground plate 112 are surrounded by a gasket 108. Herein, a plasma baffle 109 that is substantially coplanar with the substrate receiving surface of the ESC substrate support 105 prevents plasma from forming in the volume between the gasket 108 and one or more sidewalls 122.

[0031] The substrate support 105 is typically formed of a dielectric material such as a bulk sintered ceramic material such as a corrosion resistant metal oxide or metal nitride material such as aluminum oxide (Al2O3), aluminum nitride (AlN), titanium oxide (TiO), titanium nitride (TiN), yttrium oxide (Y2O3), mixtures thereof, or combinations thereof. In embodiments herein, the substrate support 105 further includes a bias electrode 104 embedded in the dielectric material of the substrate support. In one configuration, the bias electrode 104 is a clamping electrode that is used to fix (clamp) the substrate 103 to the substrate receiving surface 105A of the substrate support 105 (also referred to herein as the ESC substrate support) and bias the substrate 103 relative to the processing plasma 101 using one or more of the pulsed voltage biasing schemes described herein. Typically, the bias electrode 104 is formed of one or more conductive parts such as one or more metal meshes, foils, plates, or combinations thereof. In some embodiments, the bias electrode 104 is electrically coupled to a bias compensation module 116 that provides a clamping voltage to the bias electrode using an electrical conductor such as a coaxial transmission line 106 (e.g., a coaxial cable), such as a static DC voltage between approximately -5000V and approximately 5000V. The high voltage module 116 includes bias compensation circuit elements 116A, a DC power supply 155, and a blocking capacitor 153. A bias compensation module blocking capacitor, also referred to herein as the blocking capacitor 153, is provided between the output of the pulsed voltage waveform generator (PVWG) 150 and the bias electrode 104.

[0032] The bias electrode 104 is spaced apart from the substrate receiving surface 105A of the substrate support 105 by a dielectric material layer of the substrate support and is thus spaced apart from the substrate 103. Depending on the type of electrostatic clamping method used to hold the substrate 103 during processing within the substrate support 105, such as Coulomb ESC or Johnsen-Rahbek ESC, the effective circuit elements used to model the electrical coupling of the bias electrode 104 to the plasma 101 will vary. In the present case, the bias electrode 104 is electrically coupled to the output of a pulsed-voltage waveform generator (PVWG) 150 using an external conductor (such as a transmission line 106) disposed within the support shaft 138.

[0033] The substrate support assembly 136 further includes an edge control electrode 115 disposed below the edge ring 114 and surrounding the bias electrode 104 such that when biased, due to its position relative to the substrate 103, the edge control electrode can affect or modify portions of the generated plasma 101 that are at or beyond the edge of the substrate 103. The edge control electrode 115 can be biased by using a Pulse Voltage Waveform Generator (PVWG) 150 that is different from the Pulse Voltage Waveform Generator (PVWG) 150 used to bias the bias electrode 104. In one configuration, the first PV waveform generator 150 of the first PV source assembly 196 is configured to bias the bias electrode 104, and the second PV waveform generator 150 of the second PV source assembly 197 is configured to bias the edge control electrode 115. In one embodiment, the edge control electrode 115 is located within a region of the substrate support 105, as Figure 1 shown. Generally speaking, for a plasma processing chamber 100 configured to process circular substrates, the edge control electrode 115 is annular in shape, made of a conductive material, and configured to surround at least a portion of the bias electrode 104. In some embodiments, as Figure 1 shown, the edge control electrode 115 includes a conductive mesh, foil, or plate that is disposed at a similar distance (i.e., in the Z direction) from the surface 105A of the substrate support 105 as the bias electrode 104. In some other embodiments, the edge control electrode 115 includes a conductive mesh, foil, or plate located on or within a region of a dielectric tube 110 (e.g., AlN or Al2O3) that surrounds at least a portion of the bias electrode 104 and / or the substrate support 105. Alternatively, in some other embodiments, the edge control electrode 115 is positioned within or coupled to the edge ring 114 that is disposed adjacent to the substrate support 105. In this configuration, the edge ring 114 is formed of a semiconductor or dielectric material (e.g., AlN, Al2O3, etc.).

[0034] The plasma processing chamber 100 further includes a controller 126, which is also referred to herein as the processing chamber controller. The controller 126 herein includes a central processing unit (CPU) 133, a memory 134, and support circuitry 135. The controller 126 is used to control the process sequence for processing the substrate 103, including the substrate biasing method described herein. The CPU 133 is a general-purpose computer processor configured to be used in an industrial environment for controlling the processing chamber and its associated sub-processors. The memory 134 described herein is typically non-volatile memory and may include random access memory, read-only memory, a floppy disk or disk drive, or other suitable forms of local or remote digital storage devices. The support circuitry 135 is typically coupled to the CPU 133 and includes a cache, a clock circuit, an input / output subsystem, a power supply, etc., and combinations thereof. Software instructions (programs) and data can be encoded and stored in the memory 134 for instructing the processor within the CPU 133. The software program (or computer instructions) readable by the CPU 133 in the controller 126 determines which tasks are executable by the components in the plasma processing chamber 100. Preferably, the program readable by the CPU 133 in the controller 126 includes code that, when executed by the processor (CPU 133), performs tasks related to the monitoring and execution of the electrode biasing scheme described herein. The program will include instructions for controlling various hardware and electronic components within the plasma processing chamber 100 to perform various process tasks and various process sequences for implementing the electrode biasing scheme described herein.

[0035] During processing, the PV generators within the PV waveform generators 150 of the first PV source assembly 196 and the second PV source assembly 197 establish a pulsed voltage waveform on the load disposed within the plasma processing chamber 100. The overall control of the delivery of the PV waveforms from each of the PV waveform generators 150 in the PV waveform generator 150 is controlled by using signals provided from the controller 126. Each PV waveform generator 150 will include a PV generator (e.g., a DC power supply) and one or more electronic components, such as a high repetition rate switch, a capacitor (not shown), an inductor (not shown), a flyback diode (not shown), a power transistor (not shown), and / or a resistor (not shown), which are configured to provide the PV waveform.

[0036] The PV transmission line 157 electrically connects the output of the PV waveform generator 150 to the second filter assembly 151. The PV transmission line 158 of the second PV source assembly 197 couples the PV waveform generator 150 to the edge control electrode 115 and will include the same or similar components. The electrical conductors within the respective portions of the PV transmission lines 157, 158 can include: (a) coaxial transmission lines (e.g., coaxial line 106), which can include a flexible coaxial cable connected in series with a rigid coaxial transmission line; (b) insulated high-voltage corona-resistant mounting wire; (c) bare wire; (d) metal rod; (e) electrical connectors; or (f) any combination of the electrical components in (a) through (e).

[0037] Example of a pulse waveform

[0038] Figure 2 An example of a pulsed voltage waveform according to certain embodiments is illustrated, the pulsed voltage waveform including voltage pulses provided within the pulsed voltage waveform established at the substrate due to the delivery of voltage pulses to the bias electrode during plasma processing by use of a PV waveform generator. In some embodiments, the voltage pulses disclosed herein are a series of asymmetric voltage pulses, as Figure 2 shown. It has been found that the PV waveform established at the substrate during plasma processing can be advantageously used to control aspects of the plasma sheath formed above the substrate surface during plasma processing. Controlling the magnitude and shape of the plasma sheath formed above the substrate surface allows control of the interaction of ions with the substrate surface during processing, such as allowing control of the ion energy distribution function (IEDF), electron energy distribution function (EEDF), ion directionality, and other plasma-related characteristics. Waveform 225 is an example of an uncompensated pulsed voltage (PV) waveform established at the substrate 103 during plasma processing due to the delivery of the PV waveform to the bias electrode 104. The compensated pulsed voltage (PV) waveform seen at the substrate can alternatively be established by applying a negative voltage ramp during the ion current phase of the pulsed voltage waveform to the PV waveform provided to the bias electrode 104 by the PV waveform generator 150.

[0039] In Figure 2In [the figure], waveform 225 includes two main stages: an ion current stage and a sheath collapse stage. Two portions of waveform 225 (the ion current stage and the sheath collapse stage) can be established at substrate 103 during plasma processing. At the beginning of the ion current stage, due to the delivery of the negative portion (e.g., the ion current portion) of the PV waveform provided by PV waveform generator 150 to bias electrode 104, a voltage drop is created at substrate 103, which creates a high-voltage sheath above substrate 103. The high-voltage sheath allows plasma-generated positive ions to accelerate towards the biased substrate during the ion current stage, and thus for the RIE process, controls the amount and characteristics of the etching process occurring on the substrate surface during plasma processing. In some embodiments, it is desirable that the ion current stage generally includes a region of the pulsed voltage waveform that achieves a stable or minimally varying voltage at the substrate throughout the stage. It will be noted that significant changes in the voltage established at the substrate during the ion current stage, such as those indicated by the positive slope of waveform 225, will undesirably cause changes in the ion energy distribution function (IEDF) and / or the electron energy distribution function (EEDF), and thus result in undesired characteristics of the etched features formed in the substrate during the RIE process.

[0040] The PV waveform generated by PV waveform generator 150 may include a plurality of pulse trains (not shown). Each pulse train is constituted by a pulsed voltage waveform including a plurality of voltage pulses. In some embodiments, a bias voltage is applied during the ion current stage of each voltage pulse. In other words, the off-time T of each voltage pulse OFF occurs during the sheath collapse stage, and the bias voltage is applied during the on-time T that occurs during the ion current stage ON The on-time T ON and the off-time T OFF are configured as a percentage of the period T of each voltage pulse p The frequency of each voltage pulse can be adjusted by increasing or decreasing T p while T ON and T OFF can be adjusted by changing their T p percentage. In addition, the voltage pulse has an applied voltage V, which is defined as the peak voltage of the sheath collapse stage.

[0041] Figure 3A and Figure 3BIllustrated is that, according to certain embodiments, a train of pulses of a PV waveform generated by a PV waveform generator is delivered to a bias electrode. The PV waveform generator 150 is configured to generate a PV waveform 301 that includes multiple trains of voltage pulses, and the multiple trains of voltage pulses are based on the information provided in the parameters of a synchronization signal 303 (such as a TTL signal) provided by the controller 126. In certain embodiments, each voltage pulse of the PV waveform 301 can be triggered by each pulse of the synchronization signal 303. The characteristics of the voltage pulses within the train of voltage pulses generated by the PV waveform generator 150 are controlled by the synchronization signal 303. In some embodiments, at least one parameter of the voltage pulses within the train of voltage pulses is based on the parameters of the synchronization signal 303. In one example, whenever the PV waveform generator 150 receives a first waveform pulse 306a of the synchronization signal 303, a first train of pulses 304a can be sent. Whenever the PV waveform generator 150 receives a second waveform pulse 306b, a second train of pulses 304b can be sent.

[0042] In some embodiments, a train of pulses is sent during each waveform pulse of the synchronization signal 303. At least one parameter of the voltage pulses that make up each train of pulses, such as voltage pulse frequency, pulse on-time, pulse voltage, and combinations thereof, can be based on the parameters of each waveform pulse of the synchronization signal 303. In some embodiments, to accommodate variations in IDEF, EEDF, and undesired characteristics (such as non-uniformity of etched features on the substrate 103), the PV waveform generator 150 can be configured to deliver trains of pulses with different parameters based on one or more characteristics of the synchronization signal received by the PV waveform generator 150 from the controller 126. Advantageously, it is believed that by controlling the characteristics of portions of the pulse voltage waveform during different stages of plasma processing performed on the substrate, improved etched features can be formed on the surface of the substrate 103. For example, a higher voltage pulse frequency within the train of pulses can result in a higher etching rate at the central portion 170 ( Figure 1 ) of the substrate 103, while a lower voltage pulse frequency during the train of pulses can result in a higher etching rate at the edge portion 172 of the substrate 103. In another example, a pulse on-time (T OFF ) that is longer compared to the pulse off-time (T ON) can result in a higher etching rate on the edge portion 172 of the substrate 103, while a shorter pulse-on time results in a lower etching rate on the central portion 170 of the substrate 103. It has been found that the pulse-on time and the pulse frequency can affect other important plasma processing parameters, such as etching selectivity, bowing, and critical dimension. In another example, controlling the pulse voltage level, such as having a higher voltage level in one stage of the plasma process relative to another stage, can result in an improved ability to etch deep features in the substrate surface, a higher etching rate, and a larger plasma sheath (and vice versa for the voltage pulse repetition frequency), while a lower voltage level can be beneficially used to shape the mask and the top portion of the etched features. In another example, adjusting the rest time between the pulse trains of the voltage pulses can be used to provide additional time to pump out the etch by-products from the processing volume 129, which can improve etching uniformity, while a shorter rest time between the pulse trains can increase the substrate throughput during plasma processing. Thus, in each of the methods described below, at least one parameter of the voltage pulses in different pulse trains within the PV waveform can be adjusted during processing to achieve the desired plasma processing result. Combinations of different pulse trains with voltage pulses having different characteristics can be used to tune the plasma processing result seen on the substrate.

[0043] At least one parameter of each voltage waveform within the pulse train can be based on the parameters of each waveform pulse of the synchronization signal. In one example, the PV waveform generator 150 can distinguish the voltage waveform parameters within the pulse train based on a portion of the waveform pulses of the synchronization signal 303. In one example, the first waveform 306a of the synchronization signal 303 can have a first pulse voltage V P1 , and the second waveform 306b of the synchronization signal 303 can have a second pulse voltage V P2 , which is used to cause a change in one or more parameters of each voltage waveform within each pulse train of the associated pulse train. In one example, the first pulse voltage V P1 can indicate to the PV waveform generator 150 to generate a voltage waveform having a first pulse frequency during the first pulse train 304a, and the second pulse voltage V P2 can indicate to the PV waveform generator 150 to generate a voltage waveform having a second pulse frequency during the second pulse train 304b.

[0044] In other words, the first waveform pulse 306a may correspond to a first pulse train 304a having a voltage pulse frequency equal to the first voltage pulse frequency F1, a pulse-on time equal to OT1, and a pulse voltage of V1. The second waveform pulse 306b may correspond to a second pulse train 304b having a voltage pulse frequency equal to F2, a pulse-on time equal to OT2, and a pulse voltage equal to V2. Both the voltage pulse frequencies F1 and F2 may include different voltage pulse frequencies between 25 - 500 kHz, the pulse-on times OT1 and OT2 may include different pulse-on times between 10% and 90% of the voltage pulse period, and the pulse voltages V1 and V2 may be pulse voltages between 500 V and 15 kV.

[0045] The parameters of each waveform pulse of the synchronization signal 303 may correspond to one parameter, all parameters, or a combination of parameters of the voltage pulses applied within the pulse train. Additionally, multiple synchronization signals, each corresponding to different parameters of each pulse train, may also be used to distinguish the characteristics of each voltage pulse applied to the pulse train ( Figure 3D ).

[0046] Advantageously, based on the etch recipe and the desired etch features to be formed on the substrate 103, the synchronization signal 303 may be configured such that the parameters of the PV waveform 301 are changed during processing to obtain the desired etch profile on the substrate 103. In other words, while the waveform pulses alternate in Figure 3A , the synchronization signal 303 may be configured to control the delivery of the voltage pulses within each pulse train in any suitable order or arrangement to meet the desired etch profile.

[0047] Furthermore, the rest time between the pulse trains of the PV waveform 301 may correspond to the rest time between the waveform pulses of the synchronization signal 303. The generation of each pulse train of the voltage pulses may be triggered by the rising edge of each waveform pulse of the synchronization signal 303. In some configurations, the falling edge of each waveform pulse may trigger the PV waveform generator 150 to stop generating the pulse train. For example, the first rest time 308a ( Figure 3A ) between the first pulse train 304a and the second pulse train 304b is equal to the rest time between the first waveform pulse 306a and the second waveform pulse 306b of the synchronization signal 303. The second rest time 308b between the second pulse train 304b and the first pulse train 304a is equal to the rest time between the second waveform pulse 306b and the first waveform pulse 306a. In another example, as Figure 3B shown, the rest time between the pulse trains may be eliminated by eliminating the rest time between the waveform pulses of the synchronization signal 303.

[0048] In some embodiments, the voltage pulse frequency of each pulse train can be determined by the parameters of the corresponding waveform pulses of the synchronization signal 303. For example, the pulse voltage V of the first waveform pulse 306a P1 may correspond to the first frequency F1, while the pulse voltage V of the second waveform pulse 306b P2 may correspond to the second pulse frequency F2. In other words, the information contained in the synchronization signal 303 can be used to set and / or adjust the characteristics of the voltage pulses, such as the voltage pulse repetition frequency.

[0049] Although two different pulse trains generated based on two different waveform pulses of the synchronization signal are shown in Figures 3A to 3B , the number of different pulse trains having the same or different voltage pulse characteristics in each pulse train generated by the PV waveform generator 150 and the number of waveform pulses in each synchronization signal for creating different pulse trains for voltage pulses are not intended to be limited by the present disclosure. In addition, the number or shape of the synchronization signals for controlling the pulses of the PV waveform generator 150 is not limited by this application. Each characteristic of each voltage waveform within the pulse train can be controlled by using one or more synchronization signals. For example, different parameters of the voltage waveform constituting each pulse train can correspond to the pulse voltage levels of each synchronization signal among multiple synchronization signals, as will be described in more detail below.

[0050] Figure 3C An example of a pulse voltage waveform composed of a plurality of voltage pulses 332 within the first pulse train 304a is illustrated according to certain embodiments. For example, Figure 3C illustrates the pulse voltage waveform 330 constituting the first pulse train 304a, which includes six voltage pulses 332, each of which has a period "T p ", an on-time "OT1", and an applied voltage "V1". As described above, the first pulse train 304a is generated during the first waveform pulse 306a of the synchronization signal 303. The pulse voltage waveform 330 is generated synchronously with the first waveform pulse 306a of the synchronization signal 303. In other words, the rising edge of the first waveform pulse 306a triggers the generation of the pulse voltage waveform 330, and the falling edge of the first waveform pulse 306a triggers the PV waveform generator 150 to stop generating the pulse voltage waveform 330.

[0051] The pulse voltage waveform 330 includes a plurality of voltage pulses 332. The pulses 332 may include parameters such as the voltage pulse repetition frequency, the pulse on-time, and the pulse voltage. In addition, as described above, the parameters of the synchronization signal 303 (or multiple synchronization signals) correspond to the setting of at least one parameter of the pulse voltage waveform 330. For example, as described above, the pulse voltage V of the first waveform pulse 306a P1Corresponding to the voltage pulse frequency F1, the pulse on-time OT1, and the pulse voltage V1.

[0052] Figure 3D FIG. illustrates a PV waveform 301 generated by a PV waveform generator based on a plurality of synchronization signals according to certain embodiments. As described above, the plurality of synchronization signals may be received by the PV waveform generator 150 and used to individually define one or more characteristics of voltage pulses (not shown) within the PV waveform 301. Each synchronization signal may correspond to at least one parameter of each voltage pulse within a pulse train of voltage pulses of the PV waveform 301 transmitted by the PV waveform generator 150. In certain embodiments, each voltage pulse generated by the PV generator 150 may be triggered by each pulse of the synchronization signal.

[0053] Refer to Figure 3D , the controller 126 may transmit a first synchronization signal 303 and a second synchronization signal 340 to the PV waveform generator 150. The two synchronization signals may each correspond to at least one parameter of each voltage pulse within a pulse train. For example, the synchronization signal 303 may be the first synchronization signal and may include information for controlling or adjusting the voltage pulse frequency within each pulse train of voltage pulses. For example, when the first waveform pulse 306a of the first synchronization signal 303 has a first pulse voltage V P1 level, the PV waveform generator 150 uses or interprets the received first pulse voltage V P1 level to request the delivery of voltage pulses at a frequency F1 (i.e., 1 / T p1 ). On the other hand, when the second waveform pulse 306b of the first synchronization signal 303 has a second pulse voltage V P2 level, the PV waveform generator 150 uses or interprets the received second pulse voltage V P2 level to request the delivery of voltage pulses at a frequency F2 (i.e., 1 / T p2 ).

[0054] The second synchronization signal 340 may be used to control individual voltage pulse characteristics or parameters, such as the pulse on-time of each voltage pulse within each pulse train or the pulse voltage level of each voltage pulse within each pulse train. For example, when the first waveform pulse 342a of the second synchronization signal 340 is equal to a third pulse voltage V P3 level, the PV waveform generator 150 uses or interprets the received third pulse voltage V of the second synchronization signal 340 P3 level to request that the delivery of the voltage pulse have a first pulse on-time OT1. When the second waveform pulse 342b of the second synchronization signal 340 is equal to a fourth pulse voltage V P4 level, the PV waveform generator 150 uses or interprets the received fourth pulse voltage V of the second synchronization signal 340P4 Horizontally to require the delivery of a voltage pulse to have a second pulse-on time OT2.

[0055] Although each voltage waveform of each synchronization signal switches between two different voltage levels, each synchronization signal can switch between more than two different voltage levels, where each of the more than two different voltage levels corresponds to an additional value of a parameter of the voltage pulses in each pulse train. In one example, different voltage levels, voltage ramps, or other pulse characteristics can be used in the synchronization waveform to adjust other voltage parameters of each delivered voltage pulse within the pulse train. Other voltage pulse parameters that can be adjusted based on the information provided in the synchronization signal can include, but are not limited to, the slope of the voltage applied during a portion of the voltage pulse and / or the magnitude and duration of the voltage applied during a voltage pulse sub-portion within a portion of the voltage pulse delivered within the pulse train. In one example, such sub-portions can include stepped voltage signals delivered during one or more portions of the voltage pulses provided within the pulse train.

[0056] In addition, although Figure 3D two different synchronization signals are illustrated, more than two synchronization signals can be used to control at least one parameter of each voltage pulse within the pulse train. In one example, a third synchronization can be used to control the applied pulse voltage of each voltage pulse within the pulse train. On the other hand, the pulse voltage of the voltage waveform of the first synchronization signal 303 or the second synchronization signal 340 can additionally be used to control the applied voltage of the voltage pulses within the pulse train. For example, a first waveform pulse 342a of the second synchronization signal 340 having a third pulse voltage V P3 can correspond to a first pulse train 304a having a first pulse voltage V1, while a second waveform pulse 342b of the second synchronization signal 340 having a fourth pulse voltage V P4 can correspond to a second pulse train having a pulse voltage V2. Alternatively, in some embodiments, the controller 126 can transmit the parameters of each etch recipe step to the central controller of the PV waveform generator 150. Some or all of the parameters, such as pulse voltage, pulse-on time, or pulse frequency, can be controlled by the controller 126. In other words, each step of the process recipe can be controlled by a combination of the synchronization signals or the controller 126 or one of them.

[0057] Figure 4 illustrates the use of a plasma processing chamber (e.g., Figure 1Method 400 of a plasma processing chamber 100). Method 400 is executed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, processing devices, etc.), software (such as instructions running on a processing device, general computer system, or dedicated machine), firmware, microcode, or a combination thereof. In some embodiments, method 400 is partially executed by a controller device (e.g., Figure 1 system controller 126). In some embodiments, a non-transitory storage medium stores instructions that, when executed by a processor in the controller device, cause the controller device to execute method 400.

[0058] For simplicity of explanation, method 400 is depicted and described as a series of operations. However, the operations according to the present disclosure can occur in various orders and / or concurrently with other operations not presented and described herein. Additionally, in some embodiments, not all of the illustrated operations are executed to implement method 400 according to the disclosed subject matter. Further, those skilled in the art will understand and appreciate that method 400 can alternatively be represented as a series of interrelated states by a state diagram or events.

[0059] At block 402 of method 400, as Figures 3A to 3C shown, a first synchronization signal 303 is received by a PV waveform generator 150. The first synchronization signal is sent from a control device (such as the controller 126 of the plasma processing chamber 100).

[0060] At block 404 of method 400, as Figures 3A to 3C shown, the PV waveform generator 150 delivers a first series of voltage pulses (i.e., a first pulse train) to the bias electrode of the substrate assembly 136 based on the synchronization signal 303. As described above, the PV waveform generator 150 uses the parameters or characteristics of the first waveform pulse 306a to control at least one parameter of the first series of voltage pulses that make up the first pulse train 304a. The pulse voltage V of the first waveform pulse 306a P1 can be used by the PV waveform generator 150 as one parameter, a combination of parameters, or all of the parameters that control the waveform characteristics of the voltage pulses within the first pulse train 304a. For example, the PV waveform generator 150 can use one or more characteristics of the first waveform pulse 306a to deliver voltage pulses within the first pulse train 304a having a pulse frequency F1, a pulse on-time OT1, and a pulse voltage V1. In some cases, a single characteristic of the first waveform pulse 306a is used to control one of the characteristics of the voltage pulses within the voltage waveform 301, such as using the first voltage level V of the first waveform pulse 306a P1to control the pulsed voltage V1 applied during the duration of the first pulse train 304a, while other characteristics of the voltage pulses within the voltage waveform 301 are set and controlled by pre-configured system constants stored in the memory of the PV waveform generator 150 or the system controller.

[0061] At block 406 of method 400, as Figure 3A shown, the PV waveform generator 150 delivers a second series of voltage pulses during the pulse train 304b based on the second waveform pulse 306b of the synchronization signal 303. As described above, the parameters of the second waveform pulse 306b can correspond to at least one parameter of the second series of voltage pulses that make up the second pulse train 304b. The pulsed voltage V P2 of the second waveform pulse 306b can correspond to one, a combination, or all of the parameters or characteristics of the voltage pulses provided during the second pulse train 304b. For example, the second waveform pulse 306b can cause the voltage pulses within the second pulse train 304b to have at least one characteristic different from the voltage pulses provided during the pulse train 304a, such as a pulse train frequency F2, a pulse on-time OT2, and / or a pulsed voltage V2. This process can be repeated for each pulse train of the PV waveform 301.

[0062] Advantageously, the voltage pulse parameters within each pulse train of the PV waveform can be changed during plasma processing to obtain a desired result. For example, as an alternative or in addition to changing other parameters, the pulse frequency can be changed from F1 to F2 between the first pulse train 304a and the second pulse train 304b. For example, a higher pulse frequency can result in higher etching uniformity at the central portion 170 of the substrate 103. While a lower pulse frequency can result in higher etching uniformity at the edge portion of the substrate 103. Thus, the pulse frequency can be changed during plasma processing to obtain a desired etch profile.

[0063] However, as described above, the PV waveform 301 is not limited to two different pulse trains and the synchronization signal 303 is not limited to two waveform pulses. Additionally, the synchronization signal 303 can be used to control one parameter, all parameters, or a combination of parameters of each voltage pulse within a pulse train.

[0064] Figure 5 illustrates a method 500 for performing plasma processing in a plasma processing chamber (e.g., Figure 1 the plasma processing chamber 100) according to certain embodiments. The method 500 is executed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, processing devices, etc.), software (such as instructions running on a processing device, a general-purpose computer system, or a dedicated machine), firmware, microcode, or a combination thereof. In some embodiments, the method 500 is partially performed by a controller device (e.g.,Figure 1 is executed by the system controller 126). In some embodiments, the non-transitory storage medium stores instructions that, when executed by the controller device, cause the controller device to execute method 500.

[0065] For simplicity of explanation, method 500 is depicted and described as a series of operations. However, the operations in accordance with the present disclosure may occur in various orders and / or concurrently with other operations not presented and described herein. Additionally, in some embodiments, not all of the illustrated operations are performed to implement method 500 in accordance with the disclosed subject matter. Further, those skilled in the art will understand and appreciate that method 500 may alternatively be represented as a series of interrelated states by a state diagram or events.

[0066] At block 502 of method 500, as Figure 3D shown, a first synchronization signal 303 and a second synchronization signal 340 are generated by the controller and received by the PV waveform generator 150. In some embodiments as shown, the synchronization signals are synchronized with each other and may be transmitted from the controller 126 of the plasma processing chamber 100.

[0067] At block 504 of method 500, as Figure 3D shown, the PV waveform generator 150 delivers a first pulsed voltage waveform including a first pulse train 304a based on receiving the first synchronization signal 303 and the second synchronization signal 340. For example, at least one first parameter of the first voltage pulses constituting the first pulse train 304a may be derived from a first value of a parameter of the first waveform pulse 306a of the first synchronization signal 303. At least one second parameter of the first voltage pulses may be derived from a third value of a parameter of the first waveform pulse 342a of the second synchronization signal 340. For example, the PV waveform generator 150 uses the voltage V P1 of the first waveform pulse 306a to determine to deliver a plurality of voltage pulses at a first frequency F1, and the PV waveform generator 150 uses the voltage V P3 of the first waveform pulse 342a of the synchronization signal 340 to determine to deliver a plurality of voltage pulses with a pulse conduction time equal to OT1.

[0068] At block 506 of method 500, as Figure 3DAs shown, the PV waveform generator 150 delivers a second series of voltage pulses (i.e., the second pulse train 304b) based on the first synchronization signal 303 and the second synchronization signal 340. For example, at least one first parameter of the second voltage pulses constituting the first pulse train 304a can be derived from a second value of the parameter of the second waveform pulse 306b of the first synchronization signal 303. At least one second parameter of the first voltage pulses can be derived from a fourth value of the parameter of the second waveform pulse 342b of the second synchronization signal 340. For example, the PV waveform generator 150 uses the voltage V of the second waveform pulse 306b of the first synchronization signal 303 P2 to deliver a plurality of voltage pulses having a pulse frequency equal to F2, and the PV waveform generator 150 uses the voltage V of the second waveform pulse 342b P4 to deliver a plurality of voltage pulses having a pulse on-time equal to OT2.

[0069] Advantageously, during plasma processing, a plurality of parameters of the voltage pulses within each pulse train of the PV waveform can be changed to obtain a desired result. As an alternative or in addition to changing other parameters, the pulse on-time can be changed between pulse trains. A longer pulse on-time can result in a higher etch rate on the edge portion 172 of the substrate 103, while a shorter pulse on-time can result in a lower etch rate on the central portion 170 of the substrate 103. For example, the pulse on-time can be changed from OT1 to OT2 between the first pulse train 304a and the second pulse train 304b, and thus the average or blending of the process results from each pulse on-time setting in each pulse train or portion of the pulse train can be used to achieve an improved process result. Thus, in one example, the pulse on-time (and / or any other parameter) can be changed during plasma processing to obtain a desired center-to-edge etch profile.

[0070] Figure 6A and Figure 6B Each illustrates an example of a pulsed voltage waveform 610 delivered to a bias electrode and a synchronization signal 602 delivered to a PV waveform generator during plasma processing according to certain embodiments. In certain embodiments, the synchronization signal 602 can signal the PV waveform generator 150 to adjust at least one parameter or characteristic of the voltage waveform 610 between at least two different values of a first set of waveform pulses and the at least one parameter between at least two different values of a second set after receiving a synchronization waveform pulse.

[0071] In one example, a synchronization signal 602, such as a TTL signal, may include a plurality of waveform pulses 604 separated by periods (i.e., regions 611) of different synchronization signal voltage levels. Parameters of the rising edge 606 of each waveform pulse 604 may trigger the PV waveform generator 150 to adjust at least one parameter or characteristic 602 of the pulse voltage waveform 610 between a first set of values during each waveform pulse 604 of the synchronization signal. For example, the rising edge 606 of a synchronization signal 602 having a first voltage V P1S triggers the PV waveform generator 150 to adjust the applied pulse voltage of the pulse voltage waveform 610 between a first set of values including a first voltage V 1a and a second voltage V 1b . In one example, as shown, the rising edge 606 causes the PV waveform generator 150 to continuously deliver a first voltage pulse 621 and a second voltage pulse 622 within the period length of the waveform pulse 604, and thereby form a first pulse train of voltage pulses. The falling edge 608 of each waveform pulse 604 may trigger the PV waveform generator 150 to alternate the applied pulse voltage of the pulse voltage waveform 610 in a second set of continuously delivered third voltage pulses 623 and fourth voltage pulses 624 that vary between a second set of values including a third voltage V 2a and a fourth voltage V 2b . In some configurations, the PV waveform generator 150 may cause an adjustment of the second set of voltage pulse parameters after receiving a parameter change (such as a rising or falling edge) of the synchronization signal 602. In one example, the parameter change of the synchronization signal 602 may include a difference in the slope of the rising or falling edge of the synchronization signal. In such a case, the parameter change of the synchronization signal 602 may result in delivering a preset number of pulses based on the change of the synchronization signal 602, rather than continuing to deliver a plurality of pulses while the synchronization is maintained in a single state (e.g., maintained at V P1S ) for a period of time. The number of pulses of the voltage pulses generated after the rising time or after the falling time of the synchronization signal may be equal or may not be equal, and may be controlled by system constants and / or algorithms stored in the memory of the PV waveform generator 150 or the system controller. This will at least allow control of complex voltage pulse delivery schemes and the rest times (i.e., portions 628 of the pulse voltage waveform 610) formed between pulse trains of voltage pulses, and ensure that the PV waveform generator 150 does not need to continuously deliver or receive the synchronization signal 602 to control the characteristics of the pulse voltage waveform 610.

[0072] Although Figure 6AIllustrated is a synchronization signal 602 that causes the PV waveform generator 150 to adjust parameters between two sets of two voltage pulse values, but the number of sets of values and / or the number of values in each set of values is not limited. Additionally, each set of values may have an equal or unequal number of values. Further, although the synchronization signal 602 corresponds to one parameter of the pulsed voltage waveform 610, the synchronization signal 602 may correspond to more than one parameter of the pulsed voltage waveform 610.

[0073] Figure 6B Illustrated is a pulsed voltage waveform 610 that includes multiple parameters, which may include, as shown, portions that vary cyclically based on characteristics of the provided synchronization signal 602. In some embodiments, the multiple parameters of the pulsed voltage waveform 610 may be adjusted between different sets of values based on a single synchronization signal 602. For example, the pulsed voltage may be adjusted between a first set of values, and the pulse-on time may be adjusted between a third set of values based on the rising edge 606. The pulsed voltage may be adjusted between a second set of values, and the pulse-on time may be adjusted between a fourth set of values based on the falling edge 608.

[0074] For example, as Figure 6B shown, a first pulsed voltage V of the rising edge 606 of the synchronization signal 602 P1S may cause the PV waveform generator 150 to adjust the pulsed voltage waveform 610 between the above-described first set of values, and for each of the multiple voltage pulses 621 and 622, adjust the pulse-on time between a third set of values that includes a first pulse-on time T 1a and a second pulse-on time T 1b . The falling edge 608 of the synchronization signal 602 causes the PV waveform generator 150 to adjust the pulsed voltage waveform 610 between the above-described second set of values, and for each of the multiple voltage pulses 623 and 624, adjust the pulse-on time between a fourth set of values that includes a third pulse-on time T 2a and a fourth pulse-on time T 2b for a predetermined pulse count.

[0075] Figure 6C Illustrated is an exemplary pulsed voltage delivered to a substrate assembly and a synchronization signal delivered to the PV waveform generator according to some embodiments. Figure 6C Shown are multiple synchronization signals, each corresponding to at least one parameter of the pulsed voltage waveform 610, and the PV waveform generator 150 may use the at least one parameter to adjust the voltage pulses formed therein between different sets of values. A first synchronization signal 602A may be used to cause the PV waveform generator 150 to adjust the voltage pulses of the pulsed voltage waveform 610 in the same manner as described in Figure 6A . The first synchronization signal 602A is similar to the synchronization signal 602.

[0076] In one example, a second synchronization signal 602B including a plurality of waveform pulses 605 may also be received by the PV waveform generator 150. The second synchronization signal 602B may be synchronized with the first synchronization signal 602A. Parameters (such as the pulse voltage at the rising edge 607 of the second synchronization signal 602B) may trigger the PV waveform generator 150 to adjust at least one different parameter of the pulse voltage waveform 610 among a third set of values. For example, the rising edge 607 of the second synchronization signal 602B having a second voltage V P2S triggers the PV waveform generator 150 to alternate the pulse-on time of the voltage pulses among the above-mentioned third set of values. The falling edge 609 of the second synchronization signal 602B may trigger the PV waveform generator 150 to alternate the pulse-on time among the above-mentioned fourth set of values for a predetermined pulse count.

[0077] Figure 7 FIG. illustrates a method 700 of using a plasma processing chamber (e.g., Figure 1 plasma processing chamber 100) according to certain embodiments. The method 700 is executed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, processing devices, etc.), software (such as instructions running on a processing device, a general-purpose computer system, or a dedicated machine), firmware, microcode, or a combination thereof. In some embodiments, the method 700 is partially executed by a controller device (e.g., Figure 1 system controller 126). In some embodiments, a non-transitory storage medium stores instructions that, when executed by the controller device, cause the controller device to execute the method 700.

[0078] For simplicity of explanation, the method 700 is depicted and described as a series of operations. However, the operations according to the present disclosure may occur in various orders and / or concurrently with other operations not presented and described herein. Additionally, in some embodiments, not all of the illustrated operations are performed to implement the method 700 according to the disclosed subject matter. Further, those skilled in the art will understand and appreciate that the method 700 may alternatively be represented as a series of interrelated states by a state diagram or events.

[0079] At block 702 of the method 700, as Figure 6A shown, the PV waveform generator 150 receives the synchronization signal 602. In some embodiments, the synchronization signal 602 is transmitted from the system controller 126 of the plasma processing chamber 100.

[0080] At block 704 of the method 700, as Figure 6AAs shown, the PV waveform generator 150 delivers a pulsed voltage waveform 610 to the bias electrode of the substrate assembly 136 disposed within the plasma processing chamber 100. As will be described in the steps below, the PV waveform generator 150 can be configured to continuously deliver a plurality of voltage pulses.

[0081] At block 706 of method 700, as Figure 6A shown, the PV waveform generator 150 adjusts at least one parameter or characteristic of the pulsed voltage waveform 610 between at least two different values of a first set based on the parameters of the rising edge 606 of each waveform pulse 604 of the synchronization signal 602. As Figure 6A shown, the first pulse voltage V of the rising edge 606 of the waveform pulse 604 of the synchronization signal 602 P1S causes the PV waveform generator 150 to deliver a plurality of voltage pulses having a first set of values of the pulsed voltage waveform 610. In this example, the PV waveform generator 150 continuously delivers a first voltage pulse 621 and a second voltage pulse 622 within the period length of the waveform pulse 604, and thus forms a first pulse train of voltage pulses. In some embodiments, the PV waveform generator 150 continues to deliver voltage pulses having at least one parameter that varies between the first set of values until the falling edge 608 of the waveform pulse 604.

[0082] At block 708 of method 700, as Figure 6A shown, the PV waveform generator 150 delivers voltage pulses having a second set of values based on receiving the falling edge 608 of the waveform pulse 604 of the synchronization signal 602. As Figure 6A shown, the falling edge 608 of the waveform pulse 604 of the synchronization signal 602 causes the PV waveform generator 150 to adjust the pulsed voltage of the voltage waveform between the second set of values. In this example, the PV waveform generator 150 continuously delivers a third voltage pulse 623 and a fourth voltage pulse 624, and thus forms a second pulse train of voltage pulses. In some embodiments, the PV waveform generator 150 continues to adjust at least one parameter between the second set of values until the number of pulses equals a predetermined pulse count.

[0083] Although Figure 7 described as adjusting a single parameter of the voltage pulse between two different sets of values based on a synchronization signal, multiple parameters can be adjusted between different sets of values based on a single synchronization signal, as Figure 6B shown.

[0084] Advantageously, parameters of the pulsed voltage waveform 610 can be changed during plasma processing to obtain desired results. For example, as an alternative or in addition to changing other parameters, the pulsed voltage of the voltage pulses can be changed. As described above, a higher pulsed voltage can result in an increased ability to etch deep features in the substrate surface, a higher etch rate, and a larger plasma sheath. While a lower pulsed voltage can be beneficially used to form certain types of etched features. Thus, based on the etched features being formed, the pulsed voltage of the pulse train can be increased / decreased during plasma processing. As an alternative or in addition to other parameters of the pulsed voltage waveform 610, such as the pulse frequency or the pulse on-time, the pulsed voltage can be changed.

[0085] Figure 8 FIG. illustrates a method 800 of using a plasma processing chamber (e.g., Figure 1 plasma processing chamber 100) according to certain embodiments. Method 800 is executed by processing logic that includes hardware (e.g., circuitry, dedicated logic, programmable logic, microcode, processing devices, etc.), software (such as instructions running on a processing device, a general-purpose computer system, or a dedicated machine), firmware, microcode, or a combination thereof. In some embodiments, method 800 is partially executed by a controller device (e.g., Figure 1 system controller 126). In some embodiments, a non-transitory storage medium stores instructions that, when executed by the controller device, cause the controller device to execute method 800.

[0086] For simplicity of explanation, method 800 is depicted and described as a series of operations. However, the operations according to the present disclosure can occur in various orders and / or concurrently with other operations not presented and described herein. Additionally, in some embodiments, not all of the illustrated operations are performed to implement method 800 according to the disclosed subject matter. Further, those skilled in the art will understand and appreciate that method 800 can alternatively be represented as a series of interrelated states by a state diagram or events.

[0087] At block 802 of method 800, as Figure 6C shown, the PV waveform generator 150 receives a first synchronization signal 602A and a second synchronization signal 602B. In some embodiments, the synchronization signals are transmitted from the controller 126 of the plasma processing chamber 100.

[0088] At block 804 of method 800, as Figure 6C shown, the PV waveform generator 150 delivers a pulsed voltage waveform 610 to the bias electrode of the substrate assembly 136 disposed within the plasma processing chamber 100.

[0089] At block 806 of method 800, as Figure 6CAs shown, the PV waveform generator 150 adjusts at least one first parameter of the pulse voltage waveform 610 between a first set of values based on the parameters of the rising edge 606 of each waveform pulse of the first synchronization signal 602A. In addition, the PV waveform generator 150 adjusts at least one second parameter of the pulse voltage waveform 610 between a third set of values based on the parameters of the rising edge 607 of each waveform pulse of the second synchronization signal 602B.

[0090] As Figure 6C shown, the first pulse voltage V of the rising edge 606 of the waveform pulse 604 of the first synchronization signal 602A P1S causes the PV waveform generator 150 to adjust the pulse voltage of the voltage pulse between a first set of values. In this example, the PV waveform generator 150 continues to adjust between the first set of values until the falling edge 608 of the waveform pulse 604. The second pulse voltage V of the rising edge 607 of the waveform pulse 605 of the second synchronization signal 602B P2S causes the PV waveform generator 150 to adjust the pulse-on time of the voltage pulse between a third set of values until the falling edge 609 of the waveform pulse 605 of the second synchronization signal 602B. In this example, the PV waveform generator 150 continuously delivers the first pulse 621 and the second voltage pulse 622, and thereby forms a first pulse train of voltage. Based on the rising edge 606 of the first synchronization signal 602A, the first pulse 621 can have a voltage V 1a and a pulse-on time T 1a . Based on the rising edge 607 of the second synchronization signal 602B, the second pulse 622 can have a voltage V 1b and a pulse-on time T 1b .

[0091] At block 808 of method 800, as Figure 6C shown, the PV waveform generator 150 adjusts at least one first parameter of the pulse voltage waveform 610 between a second set of values based on the falling edge 608 of the waveform pulse 604 of the first synchronization signal 602A. In addition, the PV waveform generator 150 adjusts at least one second parameter of the pulse voltage waveform 610 between a fourth set of values based on the falling edge 609 of each waveform pulse 605 of the second synchronization signal 602B.

[0092] As Figure 6CAs shown, the falling edge 608 of the waveform pulse 604 of the first synchronization signal 602A causes the PV waveform generator 150 to adjust the pulse voltage of the voltage waveform among a third set of values for a predetermined pulse count. The falling edge 609 of the waveform pulse 605 of the second synchronization signal 602B causes the PV waveform generator 150 to adjust the pulse-on time of the voltage pulse among a fourth set of values for a predetermined pulse count. In this example, the PV waveform generator 150 continuously delivers a third voltage pulse 623 and a fourth voltage pulse 624, and thereby forms a second pulse train of voltage. Based on the falling edge 608 of the first synchronization signal 602A, the third voltage pulse 623 may have a voltage V 2a and a pulse-on time T 2a . Based on the falling edge 609 of the second synchronization signal 602B, the fourth voltage pulse 624 may have a voltage V 2b and a pulse-on time T 2b . As described above, in some embodiments, the PV waveform generator 150 continues to adjust at least one parameter among a second set of values until the number of pulses equals a predetermined pulse count.

[0093] As described above, the delivery and control of the parameters or characteristics of the PV waveform delivered by the PV waveform generator 150 can be controlled (i.e., changed) at different times during the plasma process to improve the plasma processing results achieved on the substrate. In various embodiments, at least one parameter of the PV waveform can be controlled by a synchronization signal received by the PV waveform generator 150. Thus, better control of the plasma processing results is allowed. For example, at least one parameter of the synchronization signal delivered to the PV waveform generator 150 can be changed during the plasma process to change at least one parameter of the delivered PV waveform to better achieve a desired etch profile.

[0094] Although the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the present disclosure can be designed without departing from the basic scope of the present disclosure, and the scope of the present disclosure is determined by the appended claims.

Claims

1. A method of processing a substrate in a plasma processing system, the method comprising: The waveform generator receives a first synchronization waveform signal from the controller; After receiving a first portion of the first synchronization waveform signal, the waveform generator delivers a first train of first voltage pulses to an electrode assembly disposed within the plasma processing system, wherein Based on a first waveform parameter within the first portion of the first synchronization waveform signal, at least one first parameter of the first voltage pulse is set to a first value; And After receiving a second portion of the first synchronization waveform signal, the waveform generator delivers a second train of second voltage pulses to the electrode assembly disposed within the plasma processing system, wherein the at least one first parameter of the first voltage pulse is set to a second value based on a difference in the first waveform parameter within the second portion of the first synchronization waveform signal.

2. The method of claim 1, wherein the first portion and the second portion of the first synchronization waveform signal each comprise synchronization waveform pulses.

3. The method of claim 2, wherein setting the second value based on the difference in the values of the first waveform parameters of the first portion and the second portion of the first synchronization waveform signal is based on a difference in a first characteristic of the synchronization waveform pulses.

4. The method of claim 3, wherein the first characteristic of the synchronization waveform pulses comprises a difference in voltage levels of the synchronization waveform pulses during the first portion and the second portion of the first synchronization waveform signal.

5. The method of claim 1, wherein during delivery of the first portion and the second portion of the first synchronization waveform signal, the value of at least one second parameter of the first voltage pulse and the second voltage pulse is the same.

6. The method of claim 1, wherein the first portion of the first synchronization waveform signal and the second portion of the first synchronization waveform signal further comprise: A second waveform parameter configured to provide information for adjusting a second parameter of the first voltage pulse and the second voltage pulse; And A third waveform parameter configured to provide information for adjusting a third parameter of the first voltage pulse and the second voltage pulse.

7. The method of claim 6, wherein: The first parameter, the second parameter, and the third parameter of the first voltage pulse and the second voltage pulse are selected from the group consisting of: pulse frequency, pulse on-time, and pulse voltage.

8. The method of claim 1, the method further comprising: After receiving a third portion of the first synchronization waveform signal, the waveform generator delivers a third train of first voltage pulses, wherein the third portion is the same as the first portion; And After receiving a fourth portion of the first synchronization waveform signal, the waveform generator delivers a fourth train of second voltage pulses, wherein the fourth portion is the same as the second portion.

9. The method of claim 1, wherein the first parameter of the first voltage pulse and the first parameter of the second voltage pulse are selected from the group consisting of: pulse frequency, pulse on-time, voltage, or rest time or a combination thereof.

10. The method of claim 1, wherein the first portion of the first synchronization waveform signal comprises a rising edge of a first waveform pulse of the first synchronization waveform signal, and the second portion of the first synchronization waveform signal comprises a rising edge of a second waveform pulse of the first synchronization waveform signal.

11. The method according to claim 10, wherein the first waveform parameter of the first part of the first synchronization waveform signal includes the slope of the rising edge of the first waveform pulse of the first synchronization waveform signal, and the first waveform parameter of the second part of the first synchronization waveform signal includes the slope of the rising edge of the second waveform pulse of the first synchronization waveform signal.

12. The method according to claim 10, the method further comprising: Based on the falling edge of the first waveform pulse of the first synchronization waveform signal, the delivery of the first voltage pulse is stopped.

13. The method according to claim 10, the method further comprising: Based on the falling edge of the first synchronization waveform signal, a third train of third voltage pulses is delivered, wherein at least one third parameter of the third voltage pulse is set to a third value based on the falling edge of the first synchronization waveform signal.

14. The method according to claim 1, the method further comprising: After receiving a third portion of the first synchronization waveform signal, the waveform generator delivers a third train of third voltage pulses, wherein a first parameter of the third voltage pulse is set to a third value based on the waveform parameter of the third portion of the first synchronization waveform signal; And After receiving a fourth portion of the first synchronization waveform signal, the waveform generator delivers a fourth train of fourth voltage pulses, wherein a first parameter of the fourth voltage pulse is set to a fourth value based on the waveform parameter of the fourth portion of the first synchronization waveform signal, and the first parameter of each of the voltage pulses is the same parameter.

15. The method according to claim 1, the method further comprising: The waveform generator receives a second synchronization waveform signal from the controller of the plasma processing system while the waveform generator receives the first synchronization waveform signal, Wherein at least one first parameter of the first voltage pulse is based on waveform parameters of the first portion of the first synchronization waveform signal, and at least one second parameter of the first voltage pulse is determined based on waveform parameters of the first portion of the second synchronization waveform signal.

16. A method of processing a substrate in a plasma processing system, the method comprising: A waveform generator receives a first synchronization waveform signal from a controller of the plasma processing system; The waveform generator delivers a first pulse train of first voltage pulses to an electrode assembly disposed within the plasma processing system based on a first waveform pulse provided within the first synchronization waveform signal; And The waveform generator adjusts at least one first parameter of the first voltage pulse between a first set of values based on characteristics of the first waveform pulse provided within the first synchronization waveform signal and between a second set of values based on characteristics of the first waveform pulse provided within the first synchronization waveform signal.

17. The method according to claim 16, wherein the at least one first parameter is selected from the group consisting of: pulse frequency, pulse on-time, and pulse voltage.

18. The method according to claim 16, the method further comprising: During the delivery of the first pulsed voltage waveform, the waveform generator adjusts at least one second parameter of the first voltage pulse between a third set of values and a fourth set of values based on characteristics of the first waveform pulse of the first synchronization waveform signal.

19. The method according to claim 16, the method further comprising: The waveform generator receives a second synchronization signal from the controller of the plasma processing system while the waveform generator receives the first synchronization waveform signal; And During the delivery of the first pulsed voltage waveform, the waveform generator adjusts at least one second parameter of the first voltage pulse between a third set of different values and a fourth set of values based on characteristics of the first waveform pulse of the second synchronization signal.

20. The method according to claim 16, the method further comprising: The waveform generator receives a second synchronization waveform signal from the controller of the plasma processing system; The waveform generator delivers a second pulse train of second voltage pulses to an electrode assembly disposed within the plasma processing system based on a first waveform pulse provided within the second synchronization waveform signal; And The waveform generator adjusts at least one first parameter of the second voltage pulse between a second set of values based on characteristics of the first waveform pulse provided within the second synchronization waveform signal and between a second set of values based on characteristics of the first waveform pulse provided within the second synchronization waveform signal.

21. A plasma processing chamber, the plasma processing chamber comprising: A voltage waveform generator configured to deliver a first pulsed voltage waveform to an electrode assembly disposed within the plasma processing chamber; A controller; And A memory for storing a program to be executed in the controller, the program including instructions that, when executed, cause the voltage waveform generator to: Receive a first synchronization waveform signal from the controller; After receiving a first portion of the first synchronization waveform signal, deliver a first pulse train of first voltage pulses to the electrode assembly disposed within the plasma processing system, wherein at least one first parameter of the first voltage pulse is set to a first value based on parameters of the first portion of the first synchronization waveform signal; and After receiving a second portion of the first synchronization waveform signal, a second train of second voltage pulses is delivered to the electrode assembly disposed within the plasma processing system, wherein a value of at least one first parameter of the second voltage pulses and the first pulsed voltage waveform is different based on a difference between the first portion and the second portion of the first synchronization waveform signal.

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